Doug, I think you and Kevin are talking about 2 different points during heat treatment. There won't be any cementite outside the pearlite, just as you describe, but when austenizing, there won't be any pearlite either, or we hope not. In any case, there will be more ferrite, which has essentially zero carbon in it for our purposes. For that reason, a soak would be good to get the carbon evenly distributed.